Premature and newborn babies who are cared for in an incubator require especially an effective protection from heat losses. The causes for the heat losses can be classified essentially to four different categories, namely, conduction, convection, evaporation and radiation. Conduction means the introduction of heat from the body surface to the bed on which the premature or newborn baby is located. Convention means the release of heat from the body surface to the air flow surrounding the premature or newborn baby in the incubator. Evaporation is defined as the heat of evaporation, which is generated on the body surface of the premature or newborn baby due to the drying air flow in the incubator. Finally, radiation means the heat radiation from the body surface of the premature or newborn baby to the colder surface of the incubator hood. The heat loss caused by radiation accounts for an especially considerable portion of the total heat loss.
It is described in U.S. Pat. No. 5,119,467 how this heat loss generated by heat radiation from the body surface of the premature or newborn baby to the surface of the incubator hood can be reduced. A conductive layer is integrated as a heat radiation source in the incubator hood, and this layer is connected to a temperature regulating circuit. The temperature regulating circuit comprises temperature sensors, whose signals are used to control the electric power source connected to the conductive layer.
The fact that a complicated temperature regulation with temperature sensors and a control unit therefor are necessary was found to be a drawback of the prior-art incubator hood.